how to update property of State which is stored in React Context-CodePudding

i have created state by using React Context but when i try to update propert of state in child components it do not work, sometime syntax error some time logical error, can anyone please help me ?

in App.js 
  const [car, setCar] = useState();
  <AuthContext.Provider value={{ car, setCar }}>
      
          <NavigationContainer>
            {car ? (
              <CustomerHomeStackNavigator />
            ) : (
              <Splash></Splash>
            )}
          </NavigationContainer>

      </AuthContext.Provider>

in child component i want to update its offer property but it not working, i did like this but not worked

const carContext = React.createContext();
carContext.setCar.data.offer= "1000"

car sate have this data object

 Object {
  "aud": "The_Aud",
  "data": Object {
    "address": "delhi",
    "area": "delhi",
    "city": "delhi",
    "contactnumber": "122222222222",
    "offer": "20000000"
   
  },
  "exp": 1654602892,
  "iat": 1654599292,
  "iss": "The_claim",
  "nbf": 1654599302,
  "stakeHolder": "owner",
}

CodePudding user response：

setCar is not object, is a function. you can take value with useContext, can update an object like below

const {car,setCar}= useContext(AuthContext);
setCar(prev => {...prev,data : {...prev.data,offer:"10000"}})

option 2:

var updatedCar = {...car};
updatedCar.data.offer = "1500";
setCar(updatedCar)

CodePudding user response：

setCar it is function, so for update you must call function instead of simple variable assignment. Next for getting context you must use useContext hook or static field context if you are going to use class components. You can't use createContext for get context value, it is only for create context object.

const { car, setCar } = useContext(AuthContext)
// ...
setCar(data)

See doc for more details https://reactjs.org/docs/context.html#updating-context-from-a-nested-component